Down‐regulating Myoferlin inhibits the vasculogenic mimicry of melanoma via decreasing MMP‐2 and inducing mesenchymal‐to‐epithelial transition

Vasculogenic mimicry (VM) constitutes a novel approach for tumour blood supply and contributes to tumour metastasis and poor prognosis in patients with melanoma. Myoferlin (MYOF), a type II membrane protein involved in membrane regeneration and repair, is elevated in several malignant tumours, especially in advanced melanomas. This study aims to investigate the role and mechanism of MYOF in the regulation of VM. VM structures were found in 14 of 52 tested melanoma samples, and high MYOF expression correlated with VM structures. According to Kaplan–Meier survival curves, VM channels and elevated MYOF expression both correlated with poor prognosis in melanoma patients. Down‐regulation of MYOF by siRNA severely impaired the capability of A375 cells to form VM structures in vitro. Further studies demonstrated MYOF knockdown inhibited cell migration and invasion, which is required for VM formation, via decreasing MMP‐2 expression as evidenced by Western blotting, RT‐RCP and ELISA results. SB‐3CT, a specific inhibitor of MMP‐2, showed similar inhibiting effects with siMYOF, further supporting that MYOF down‐regulation inhibits MMP‐2 expression to affect VM formation. Moreover, MYOF knockdown suppress VM formation by A375 cells by inducing mesenchymal‐to‐epithelial transition (MET). After down‐regulating MYOF, focal adhesions were enlarged and A375 cells developed into a clear epithelial morphology. Such cells acquired the expression of E‐cadherin at adherens junctions along with a loss of mesenchymal markers, such as Vimentin and Twist1. In conclusion, MYOF plays an important role in VM and knockdown of MYOF suppresses VM formation via decreasing MMP‐2 and inducing MET in A375 melanoma cells.     

中国野生凤仙花属物种多样性和地理分布数据集

凤仙花属(Impatiens)植物主要分布于旧世界的热带和亚热带山区, 对生长环境要求极度严苛, 深入分析其地理分布格局与特征, 可为种质资源调查和利用提供理论依据。本研究通过系统检索文献资料, 更新了该属植物物种名录, 整合其地理分布、海拔、特有性等信息, 建立了中国野生凤仙花属植物地理分布数据库。截至2022年3月, 中国共记载野生凤仙花属植物352种(包含18变种1亚种1变型), 其中中国特有种273种。除上海市外, 中国其他各省级行政区均有野生凤仙花属植物分布, 其中云南省分布有165种, 其次为四川省(119种)和西藏自治区(69种)。县级尺度上, 贡山独龙族怒族自治县和腾冲市以51种并列物种丰富度第一, 其次是福贡县(42种)。中国野生凤仙花属的分布总体呈现以热带、亚热带为中心向高纬度和高海拔区域扩散的格局, 广义横断山区、西藏南部地区、滇黔桂喀斯特区域、长江中下游等地为凤仙花属植物集中分布的热点地区。     

Enhancement of activity of cross-linked enzyme aggregates by a sugar-assisted precipitation strategy: technical development and molecular mechanism

The precipitation of enzyme causes the major activity loss in the conventional protocol for CLEAs preparation. Herein, a sugar-assisted strategy was developed to minimize the activity loss in the step of enzyme precipitation by adding sugar as the stabilizer, which contributed to improve the activity yield of resulting CLEAs. Penicillin G acylase (PGA) was employed as a model enzyme. The effects of glucose, sucrose and trehalose on the activity yields of CLEAs were investigated. The highest activity was obtained in the case of adding trehalose. Confocal laser scanning microscopy and Fourier transform infrared spectroscopy showed that the polar microenvironment and the secondary structure of native enzyme were preserved to some extent when PGA was prepared as sugar-assisted CLEAs, resulting in PGA's higher activity than sugar-free CLEAs. Scanning electron microscope revealed the different inner morphologies, and the kinetic studies showed the higher affinity and resist-inhibition capacity of sugar-assisted CLEAs. Furthermore, stability experiments demonstrated that CLEAs prepared in sugar-assisted strategy remained higher thermal stability when it was incubated at high temperature.     

Enzymatic saccharification of pretreated corn stover in a fed-batch membrane bioreactor

Enzymatic hydrolysis of corn stover was performed in an integrated membrane bioreactor (MBR) incorporating a 10 kDa flat sheet polysulfone membrane to increase cellulose conversion and to reduce enzyme dosage. Several pretreatment methods and semi-continuous MBR were examined to investigate their effect on the glucose yield and enzyme utilization efficiency. Compared with conventional batch reactor (CBR), cellulose conversion increased by 5% in a MBR because of the removal of glucose and cellobiose inhibitors. More than 15% increment in cellulose conversion was obtained using fed-MBR, and the reaction rate improved significantly. Enzyme utilization efficiency in a fed-batch MBR were 1.94-fold of CBR and 1.34-fold of fed-CBR for corn stover pretreated by soaking in aqueous ammonia and 3.31-fold of CBR and 1.32-fold of fed-CBR for corn stover pretreated by diluted sulfuric acid?Csodium hydroxide.     

A New Method for Xenogeneic Bone Graft Deproteinization: Comparative Study of Radius Defects in a Rabbit Model

Background and Objectives

Deproteinization is an indispensable process for the elimination of antigenicity in xenograft bones. However, the hydrogen peroxide (H₂O₂) deproteinized xenograft, which is commonly used to repair bone defect, exhibits limited osteoinduction activity. The present study was designed to develop a new method for deproteinization and compare the osteogenic capacities of new pepsin deproteinized xenograft bones with those of conventional H₂O₂ deproteinized ones.

Methods

Bones were deproteinized in H₂O₂ or pepsin for 8 hours. The morphologies were compared by HE staining. The content of protein and collagen I were measured by the Kjeldahl method and HPLC-MS, respectively. The physical properties were evaluated by SEM and mechanical tests. For in vivo study, X-ray, micro-CT and HE staining were employed to monitor the healing processes of radius defects in rabbit models transplanted with different graft materials.

Results

Compared with H₂O₂ deproteinized bones, no distinct morphological and physical changes were observed. However, pepsin deproteinized bones showed a lower protein content, and a higher collagen content were preserved. In vivo studies showed that pepsin deproteinized bones exhibited better osteogenic performance than H₂O₂ deproteinized bones, moreover, the quantity and quality of the newly formed bones were improved as indicated by micro-CT analysis. From the results of histological examination, the newly formed bones in the pepsin group were mature bones.

Conclusions

Pepsin deproteinized xenograft bones show advantages over conventional H₂O₂ deproteinized bones with respect to osteogenic capacity; this new method may hold potential clinical value in the development of new biomaterials for bone grafting.     

Th cell-independent immune responses to chimeric hemagglutinin/simian human immunodeficiency virus-like particles vaccine

CD4(+) Th cells are believed to be essential for the induction of humoral and cellular immune responses. In this study we tested the effect and possible mechanisms of the major antigenic component in influenza, hemagglutinin (HA), in helping HIV Env to induce immune responses in CD4(+) T cell knockout (CD4 KO) mice. Simian HIV virus-like particles (SHIV VLPs) or phenotypically mixed chimeric influenza HA/SHIV VLPs were used as immunogens to immunize CD4 KO mice either i.p. or intranasally (i.n.). We found that chimeric HA/SHIV VLPs significantly induced a greater IgG Ab response in both i.p. and i.n. immunized mice and a greater IgA Ab response in mucosal washes in i.n. immunized mice compared with SHIV VLPs. Importantly, chimeric HA/SHIV VLPs induced approximately 3-fold higher neutralizing Ab titers against HIV 89.6 than SHIV VLPs in the absence of CD4(+) T cell help. There was also approximately 40% more specific lysis of the HIV Env-expressing target cells in chimeric HA/SHIV VLP-immunized than in SHIV VLP-immunized CD4 KO mouse splenocytes. Moreover, we have found that chimeric HA/SHIV VLPs could efficiently bind and activate dendritic cells and stimulate the activated dendritic cells to secret TNF-alpha and IFN-gamma. Therefore, chimeric HA/SHIV VLPs could efficiently prime and activate APCs, which could, in turn, induce immune responses in a CD4(+) T cell-independent manner. This study suggests a novel adjuvant role of influenza HA as well as a new strategy to develop more effective therapeutic vaccines for AIDS patients with low CD4(+) T cell counts.     

Multimode Optical Fiber Surface Plasmon Resonance Signal Processing Based on the Fourier Series Fitting

Multimode optical fiber is widely used because of its large core size, strong light-gathering ability, and remote on-line sensing ability in various environments. Due to the mode coupling and polarization loss, the signal curve obtained has wide full width at half-maximum (FWHM) and small peak value. Therefore, efficient methods to calculate the resonant wavelength are required. This paper presents a method to process the surface plasmon resonance curve (SPR) based on the Fourier series fitting. The calculated resonant wavelength is obtained with one-dimensional extremum-search method. Experiment results show the proposed method can accurately calculate the resonant wavelength of high concentration solution. Additionally, the method has higher sensitivity and is unaffected by the light source fluctuation. This method has potential value in processing the SPR signal of the multimode optical fiber.     

Increasing matrix stiffness upregulates vascular endothelial growth factor expression in hepatocellular carcinoma cells mediated by integrin β1

Matrix stiffness as a novel regulation factor involves in modulating the pathogenesis of hepatocellular carcinoma (HCC) invasion or metastasis. However, the mechanism by which matrix stiffness modulates HCC angiogenesis remains unknown. Here, using buffalo rat HCC models with different liver matrix stiffness backgrounds and an in vitro cell culture system of mechanically tunable Collagen1 (COL1)-coated polyacrylamide gel, we investigated the effects of different matrix stiffness levels on vascular endothelial growth factor (VEGF) expression in HCC cells and explored its regulatory mechanism for controlling HCC angiogenesis. Tissue microarray analysis showed that the expression levels of VEGF and CD31 were gradually upregulated in tumor tissues with increasing COL1 and lysyl oxidase (LOX) expression, indicating a positive correlation between tumor angiogenesis and matrix rigidity. The expression of VEGF and the phosphorylation levels of PI3K and Akt were all upregulated in HCC cells on high-stiffness gel than on low-stiffness gel. Meanwhile, alteration of intergrin β1 expression was found to be the most distinctive, implying that it might mediate the response of HCC cells to matrix stiffness simulation. After integrin β1 was blocked in HCC cells using specific monoclonal antibody, the expression of VEGF and the phosphorylation levels of PI3K and Akt at different culture times were accordingly suppressed and downregulated in the treatment group as compared with those in the control group. All data suggested that the extracellular matrix stiffness stimulation signal was transduced into HCC cells via integrin β1, and this signal activated the PI3K/Akt pathway and upregulated VEGF expression. This study unveils a new paradigm in which matrix stiffness as initiators to modulate HCC angiogenesis.